Aspects of the present disclosure and embodiments thereof include methods and systems for adjusting aspects of images. For example, the methods and systems may be employed to control line width in image objects, such as, for example, text and line art. Embodiments will be described with reference to line width adjustment. However, embodiments may be applied to the adjustment of other aspects of image objects.
It should be noted that the term line, or lines, is meant to refer herein to any relatively thin image object, including, but not limited to, curves and circles.
Many images include thin lines. For example, the characters of text are considered to be made up of thin lines and curves. Additionally, many business forms include lines and grids for separating portions of a document. Many drawings are made up of discreet thin lines. It is desirable to be able to adjust images in order enhance or improve their appearance. For instance, it may be desirable to adjust the thickness of lines in an image.
For example, one way to adjust the darkness or lightness or enhance the contrast of a document being printed or photocopied is to adjust the thickness of lines. Additionally, it may be desirable to adjust the thickness of lines in an image in order to compensate for a drift or imperfection in an image rendering system. For instance, an ink or toner may spread or be absorbed by a print media more or less readily than anticipated. If an ink spreads more readily than an ideal or anticipated amount, then, for example, a white line or feature printed on a black, gray or colored background, might appear thinner than desired or may be completely filled in by spreading colorant from neighboring portions of an image. If an ink or toner or other colorant spreads less readily than anticipated, then a black, gray or colored line may appear thinner than desired. By adjusting a digital representation of the image or selected image objects of the image to be larger or thicker than originally called for, it is possible to compensate for such variations in colorant and print media behavior.
U.S. Patent Application Publication US2001/0038712 A1 to Loce, et al. published Nov. 8, 2001, entitled LOOSE GRAY SCALE TEMPLATE MATCHING FOR IMAGE PROCESSING OF ANTI-ALLI[A]SED [LINES], discusses methods for controlling the width of lines in association with loose-template matching. U.S. Pat. No. 6,678,414 B1 to Loce, et al., which issued Jan. 13, 2004, also discusses line width control in the context of template matching. The disclosures of these documents are totally incorporated herein by reference.
Template matching techniques require a relatively large amount of system memory and/or data storage resources. Furthermore, template matching techniques require that a relatively large number of data lookup and comparison procedures be performed.
Also, template matching techniques typically operate on image structures of a very specific size, shape, and orientation. Hence, the templates designed for one application tend to be useless for another related application, and a complete redesign of templates is required even if the problems are quite similar. For example, templates designed to modify the width of thin lines are likely to be useless for modifying the width of slightly wider lines. Hence, a significant redesign effort can be required for small variations of an application.
There has been a desire for line width control techniques with reduced system storage requirements. Additionally, there has been a desire for line width control techniques that do not require, or require fewer, data lookups and comparisons. Further, there is a desire for line width control methods that can be efficiently adapted to related applications, thereby greatly reducing the design effort.